The Health State of the Cryosphere

The term cryosphere is used to refer to all portions of the Earth surface where water appears in solid form. This includes the snow cover; sea, lake and river ice; glaciers, ice caps and ice sheets; and permafrost. The aim of this contribution is to present the current state of the cryosphere. Emphasis will be given to sea ice and continental ice masses (glaciers, ice caps and ice sheets), and the contribution of the losses from the latter to sea level rise (SLR).

Optical sensing of the fatigue damage state of CFRP under realistic aeronautical load sequences

We present an optical sensing methodology to estimate the fatigue damage state of structures made of carbon fiber reinforced polymer (CFRP), by measuring variations on the surface roughness. Variable amplitude loads (VAL), which represent realistic loads during aeronautical missions of fighter aircraft (FALSTAFF) have been applied to coupons until failure. Stiffness degradation and surface roughness variations have been measured during the life of the coupons obtaining a Pearson correlation of 0.75 between both variables. The data were compared with a previous study for Constant Amplitude Load (CAL) obtaining similar results. Conclusions suggest that the surface roughness measured in strategic zones is a useful technique for structural health monitoring of CFRP structures, and that it is independent of the type of load applied. Surface roughness can be measured in the field by optical techniques such as speckle, confocal perfilometers and interferometry, among others.